Wikipedia:
:Tone refers to the use of pitch in language to distinguish words. All languages use intonation to express emphasis, emotion, or other such nuances, but not every language uses tone to distinguish meaning outright. When this occurs, tones are equally important and essential as phonemes (discrete sounds, for example, /t/, or /d/), and they are referred to as '''tonemes'''.
:Languages that make use of tonemes are called '''tonal languages'''. The majority of languages in the world are tonal languages.